The invention relates to an image forming apparatus that is suitable for, for example, a color electrophotographic printer including a heater that heats a medium for image formation.
In an existing image forming apparatus, a heater of a fixing unit is coupled to a commercial AC power supply through a triac (a bidirectional thyristor). The image forming apparatus applies an AC voltage that is supplied from the commercial AC power supply to the heater in response to on-operation by the phase control of the triac, thereby controlling heating temperature of the heater (for example, Japanese Unexamined Patent Application Publication No. 2013-235107).